Posted by **killie** on Thursday, April 30, 2009 at 7:01pm.

I am very confused about the concepts of..

sin è = sin(180 - è)

sin (180 + è)= -sinè

tan (180 - è) = -tanè

and how the final answer was found in this problem...

Find cos 510:

cos510=cos(540-30)

=-cos30

=-s.r3/2

i dont understand how we went from -cos 30 to -s.r3/2 ?

## Answer This Question

## Related Questions

- Trig - 4. Asked to simplify the expression sin(180−è), Rory volunteered ...
- Trig - A. Find simpler, equivalent expressions for the following. Justify your ...
- trig - solve for the equation x sin x= -.35 180<x<270 sin x= .2 90<x<...
- math - tan(180-x)sin(360-x)cos90-x)cos(-x)/sin(x-180)cos(450+x)tan(180-x)
- Trig - Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < ...
- calculus - I need help on finding the local linear approximation of tan 62 ...
- maths - Choose the two options which are true for all values of x 1) cos (x) = ...
- Trig (Last URGENT) - sin2x+cosx=0 , [-180,180) = 2sinxcosx+cosx=0 = cosx(2sinx+1...
- trigonometry - is this correct? sin 255degrees 225 = 180 + 45 sin(225) = sin(180...
- solving trig. equations - tan(3x) + 1 = sec(3x) Thanks, pretend 3x equals x so ...

More Related Questions